Perfectionism is the most anti-natural notion we ever had.

Nothing in Nature is perfect. They are grand, awesome, beautiful but not perfect. Right from quantum level to relativistic cosmological scale nothing seems to be perfect. Perfection is an abstraction that our minds create and project on reality and suffer when betrayed.
Yet logic, rationalism, science strive to be perfect. We strive to be perfect too as this notion urges us to excel. If we look at evolution, at the biological scale, it is never after perfect but only as good as the situation demands.
As we move from mechanistic to organic world view, perfectionism is becoming a questionable idea.

Perfectionism is only an idea and it will remain as an "ideal." Usually it is used as a model for the purposes of understanding a system or hypothesis. I do not know which logic, rationalism or science makes perfection a requirement and suffers from it. On the other hand, perfection provides a guidepost of abstraction. Science, especially thermodynamics, makes amply clear the moral hazards of striving for perfection, so does old tried and explored - not necessarily true - religions (to look at the the other extreme). You can also find examples of the same in every walk of life. So perfectionism is not a standard, but just ideal signpost at infinity. I need to squint my eyes to read it. ;-)

Mar 26 2013:
With the suspended carbon part per million over 385 in the atmosphere, we have changed our natural world for good. Our seas are acidic now, whole ranges of corals have vanished, the polar caps have shrunk alarmingly - all because we wanted things perfect.